1. Field of the Invention
The subject invention relates generally to fire simulation systems for training municipal, military, and other firefighter trainees as to the preferred procedures for suppressing and ultimately extinguishing fires. More particularly, the invention. relates to a firefighter training system which is operable to produce an indication of a flashover as a consequence of improper fire extinguishing procedures on the part of the trainees.
2. Description of the Related Art
Conventional firefighter training practices typically provide for the combustion of flammable materials, such as wood, straw, and other organic and inorganic materials, which are to be extinguished by the trainee upon the application thereon of sufficient quantities of an appropriate extinguishing agent. The extinguishing agent that is most commonly utilized is water, due principally to its availability, cost and widespread usage as a fire extinguishing material. However, these conventional training practices have come under scrunity in recent years as a result of the relatively high injury rate, adverse environmental impact, and limited training effectiveness and trainee throughput that is associated with such practices. For example, the National Fire Protection Association (NFPA) reports that in the United States alone, nearly 6,000 training-related injuries were sustained by firefighters in 1988. Nevertheless, live fire training is a crucial and necessary component of firefighter training, for it most closely represents the overall environment a firefighter is likely to encounter during a genuine fire emergency, Unfortunately, conventional live fires that are set for the purpose of firefighter trainee education suffer from many of the very same hazards that are associated with genuine fire emergencies--unpredictability of fire propagation and its response to trainee action. As a consequence of these characteristics, it is oftentimes necessary for the trainee supervisors to themselves suppress the live fire prior to rendering perhaps life-saving assistance to a fallen trainee. Furthermore, because the very nature of a conventional live fire is unpredictability, it is not possible to accurately and readily reproduce a desired fire condition for a succession of firefighter trainees.
In an effort to address the foregoing deficiencies in firefighter training, live fire simulator systems have been implemented since the early 1970's which provide for, among other features, the substitution of various controllable arrangements of propane and natural gas-operable burners located within dedicated "burn rooms" for the prior practice of igniting various flammable props (i.e., wood or straw bundles) or even buildings to be razed. Illustrative of the newer generation of live firefighter training simulators is that disclosed in U.S. Pat. No. 4,303,396 and assigned to the United States of America as represented by the Secretary of the Navy. The simulator disclosed in this referenced patent, which is hereby incorporated by reference, provides a plurality of chambers, each of which can be provided with a fire from a fuel burner that is representative of a variety of different types of fires. This simulator is useful in educating firefighter trainees as to some general principles of fire extinguishment, such as spray nozzle control and various extinguishing agent application techniques. However, it does not simulate certain "real life" fire situations, such as flashover, that a firefighter may encounter during the course of combating of a genuine fire emergency of the type that can be present in a generally enclosed space. As used herein, the term "flashover" refers to the spontaneous combustion and/or explosion of heated gases which collect adjacent the ceiling of a room as a consequence of the various gases emitted from burning material having attained their flash point temperatures. Flashover manifests itself in the form of a fireball which explodes downwardly from the ceiling to the floor. As the fireball can attain temperatures in excess of 1,000.degree. F. (538.degree. C.), which is far greater than the temperature at which conventional firefighter survival suits are rated, the occurrence of a flashover is oftentimes fatal to all personnel in the vicinity of the fireball. Additionally, the concussive effect of the downward explosion of the fireball can disable personnel not in the immediate vicinity of the flashover.
Because flashover can have such a profound impact on the health, safety and performance of firefighters, it is desirable to properly educate firefighters as to the fire extinguishing techniques which are successful in preventing flashover from occurring in the first instance. One commonly used method for inhibiting the occurrence of flashover is to periodically spray with water the ceiling of the room in which the fire is present, thereby cooling the gases located adjacent to the ceiling.
Efforts to incorporate flashover precursor simulation in prior live fire simulators have not been entirely successful and can present unduly hazardous conditions for trainees. For example, an attempt has been made to provide flashover prevention training by monitoring generally the manner in which water is applied to the fire. In instances where improper watering techniques are used, the fire is made to expand and rollover conditions are caused to develop three to five feet (1-1.5 m) across the ceiling. Unfortunately, this can give rise to hazardous conditions in the event that the trainees are in undesirably close proximity to the burners.
In view of the foregoing limitations of the prior art, it is an object of the subject invention to provide a flashover simulation for firefighter training which is operable in a highly controllable manner and to provide a visual, aural and thermal indication of flashover once predetermined conditions have been met.
A further object of the subject invention is to simulate flashover arising from a variety of different fire types and occurring when a variety of different extinguishing agents, such as water, foam, CO.sub.2 and other agents, are in use.
Yet another object of the subject invention is to provide flashover simulation for firefighter training which is responsive to a range of variable user-selectable parameters.
These and other objects and advantages will become apparent from a reading of the following detailed description of the preferred embodiment.